Meteorologists with the National Weather Service issued a winter storm watch that will be in effect tonight through Friday evening. A storm system with ample moisture is predicted to move into the area, dropping an estimated 1 to 3 inches of snow on the valley floors in Jackson County.

"It could snow all the way down to sea level," said Chuck Glaser, meteorologist in the National Weather Service's Medford office. "(It's a) good day to stay home."

Accumulations of snow and ice could impact travel, particularly on the mountain passes.

A low-pressure system, inbound from the Arctic, is expected to head off into the Pacific Ocean, picking up moisture before drifting back inland. When it reaches the Rogue Valley, already in the grip of a cold front, the snow should start falling. Weather officials believe it will start between 4 and 8 a.m. Friday.

"It might even be earlier," Glaser said. "It just depends on the timing."

Up to 6 inches is expected at elevations of 1,000 feet and above, with up to 8 inches predicted for the Siskiyous and higher elevation passes.

"Whatever does fall isn't going to melt really fast," Glaser said.

Nighttime low temperatures for Thursday and Friday are expected to drop into the low 20s, dipping into the low teens by the weekend, even though snow is expected to cut out by Saturday.

"It should be pretty much done by then," Glaser said.

Reach Mail Tribune reporter Ryan Pfeil at 541-776-4468 or by email at rpfeil@mailtribune.com.